The present invention relates to a robot vehicle for hot-line job used in outage-free maintenance techniques carried out without interrupting the supply of electric power during wiring work and maintenance on high voltage transmission and distribution lines.
A robot vehicle for hot-line job is a vehicle for high-place work having two-armed manipulators for operations and a third arm for suspending heavy matters to be supported on an electrical wire, on a manipulator base mounted on the end of a boom thereof, and wiring work and maintenance are carried out by operating them from an operation cabin on the ground in a robot vehicle or from an operation panel on a bucket provided at the end of the boom.
When all of actuators for driving the two-armed manipulators and third arm are constituted by hydraulic actuators, high positioning accuracy can not be achieved for the two-armed manipulators and, as a result, it becomes difficult to conduct teaching-playback and automatic operations based on a correcting function associated therewith. However, this makes it possible to reduce the size and weight of the third arm which has the function of suspending heavy matters and which is not required to be so high in positioning accuracy. Conversely, when all of the driving mechanisms for the two-armed manipulators and third arm are constituted by electrical actuators, high accuracy is achieved by the two-armed manipulators to facilitate corrective automatic operations such as approaching an object to be worked, whereas the third arm becomes large and heavyweight.
Under such circumstances, there is a need for a robot vehicle for hot-line job in which highly accurate positioning of a manipulator can be achieved to enable remote operations by an operator and corrective automatic operations such as approaching an object to be worked and which is loaded with a compact and lightweight third arm having a function of suspending heavy matters.
In a robot for working on hot lines, a robot which an operator boards on a bucket at the end of a vehicle for high-place work and he operates a manipulator therein, is called xe2x80x9can on-board type robot for working on hotlinesxe2x80x9d . One possible pattern of the occurrence of an electric shock of an operator of a man-operated robot for working on hot lines is as shown in FIG. 7 in which an operator 56 touches a hot line 61 in a bucket 55. In this case, a voltage between the hot line 61 and the ground causes a current to flow through a path extending from the hot line 61 through the operator 56, the bucket 55, a boom portion (a third boom 54, a second boom 53 and a first boom 52), a vehicle 51 and to the ground. In FIG. 7, 57 designates an operation panel; 58 designates a manipulator mounting portion; 59 designates a first insulated arm portion; and 60 designates a second insulated arm portion.
For the safety of operators, safety standards for vehicles for high-place work are defined by Japan Vehicle Body Industries Association. It is specified by the standards that a leakage current should not exceed 0.5 mA as the insulating performance of a vehicle for high-place work. Further, it is specified that a voltage equivalent to twice a line voltage must be applied as a test voltage according to the standard because a leakage current varies depending on the applied voltage. A robot for working on hot lines according to the present invention is aimed at operations on hot lines at 23 kV. Therefore, referring to the electric shock shown in FIG. 7 at a man-operated robot for working on hot lines, the leakage current that flows through the operator must be 0.5 mA or less when a voltage of 46 kV is applied. For this purpose, as shown in FIG. 8, hitherto the insulation characteristics have been ensured by forming the end of the third boom 54 with an FRP hollow cylinder 62 which is an insulating material.
However, in order to keep the leakage current at 0.5 mA or less in rainy weather with the above-described configuration, the creepage distance of insulation must be long, and this has resulted in a need for always keeping the third boom in an extended state in which it spans 2 meters or more. Therefore, in rainy weather, the third boom 54 must be extended to a span of 2 meters or more even when the hot line to be worked is in a relatively low position. In this case, the weight of the manipulator portion can reduce the balance of the vehicle body to support the same and can cause the vehicle body to fall down, which makes an operation difficult or impossible. Even if an operation can be carried out with the third boom extended to a span of 2 meters or more, continued rain fall on the third boom reduces the property of shedding water of the surface of the third boom, i.e., water repellency, to make it impossible to keep the leakage current at 0.5 mA or less. When rain falls on the surface of the third boom with a voltage applied thereto, discharge occurs on the boom surface to deteriorate the FRP resin layer on surface of the third boom rapidly, thereby reducing water repellency rapidly. This makes it impossible to keep the leakage voltage at 0.5 mA or less.
When foreign substances such as sand stick to the third boom, the third boom is damaged in the area of a rotor which receives the third boom 54 during the extension and retraction of the boom, which results in a reduction of the water repellency of the third boom in a long term.
FIG. 8 is a sectional view of a structure of a conventional boom portion. In FIG. 8, a third boom 54 is an insulator which supports a manipulator portion and which is constituted by an FRP hollow cylinder 62. Since the FRP hollow cylinder 62 is an insulator, even if an operator 56 touches a hot line in a state as shown in FIG. 7 in sunny weather, the leakage current can be kept at 0.5 mA or less for a voltage of 46 kV at the hot line if the third boom 54 is extended to a span of 0.5 meters.
With the conventional structure shown in FIG. 8, however, a test on it resulted in a rapid increase of the leakage current from the third boom 54 when the surface of the third boom 54 was exposed to dirty water with a voltage applied the third boom 54. Therefore, the third boom 54 with such a structure has a leakage current of 0.5 mA or more in rainy weather, and an operator of the robot for working hot lines may have an electric shock when he or she touches the hot line.
In the case of a distribution line voltage in a 6 kV class, it is possible to maintain a level of insulation to withstand a breakdown voltage which is required to prevent phase shorting accidents by covering exposed metal regions of the manipulator and the actuator with an insulating protective cover. In the case of a voltage in a 22 kV class, a large insulation distance must be kept between the insulating protective cover and the metal regions to withstand a breakdown voltage, which has resulted in a problem in that no manipulator can be provided for practical use.
When an electrical actuator is used as the manipulator of a robot vehicle for hot-line job used in outage-free maintenance techniques for the maintenance of distribution of electricity, in order to prevent an accidental electrical shock to a human being, the end of the boom is constituted by an insulator; a generator for driving the manipulator and the like is mounted on a mount base; and electrical insulation is maintained between the vehicle and the mount base. Further, an insulated portion is provided on a forearm of a manipulator to prevent a ground fault caused by a manipulator and a phase shorting accident which occurs when tools mounted at the ends of two manipulators or the ends of the manipulators touch hot lines in different phases simultaneously during an operation.
Although an accidental electrical shock to a human being can be prevented by the prior art, there has been a problem in that it is not possible to prevent a phase shorting accident which occurs when the elbows of two manipulators or the elbow and the upper arm thereof or the upper arms thereof simultaneously touch hot lines in different phases as a result of malfunction of the manipulators and the booms themselves or an erroneous operation by the operator because the electrical actuators provided at the elbows and upper arms of the two manipulators are electrically connected through an robot controller.
Further, in the case of a robot vehicle for hot-line job which deals with high voltages, in order to improve safety by preventing a physical injury of an operator caused by an electric shock and damage to electronic devices caused by a short and ground fault, earthing is carried out through a grounding operation to connect the main bodies of the electronic devices and a ground wire electrically, and this results in a need for earthing at each movement to a site of operation. This operation is carried out by an operator, and only a visual determination is made on the physical state of grounding. Under such circumstances, it is desired to allow real time unattended determination of a state of electrical grounding in order to prevent an operator from failing to carry out earthing.
In addition, slide shafts which provided on a two-armed robot have moved back and forth relative to an object to be worked during an operation of each robot or have slid back and forth simultaneously at both arms in order to allow them approach the object to be worked. In the prior art, however, since the slides moves only in parallel with each other with the distance between the two robots fixed, it has been difficult work on an object interposed between the robots because of such a configuration.
When the robots are mounted at an increased interval to solve this, a problem arises in that the robots will occupy a larger space and become heavier. In order to allow the mounting interval of the robots to be decreased while they are idle and to allow the interval to be increased to put an object to be worked therebetween during an operation, another shaft must be added, and the addition of a shaft is problematic from the viewpoint of weight, space, cost etc.
It is a first object of the invention to provide a robot vehicle for hot-line job comprising a compact and lightweight third arm in which a manipulator can be positioned with high accuracy, which allows a remote operation by an operator and an automatic operation based on teaching, playback and a correcting function associated therewith and which has a function of suspending a heavy object to be supported on an electric wire.
It is a second object of the invention to provide a structure of a boom of a vehicle for high-place work for wiring whose water repellency can be maintained for a long period of time and which has no risk of an electric shock in a state wherein the boom is extended even during an operation of a robot for working on hot lines in rainy weather.
It is a third object of the invention to prevent phase shorting accidents of a manipulator that occur when two manipulator simultaneously touch hot lines in different phases due to malfunction and an erroneous operation.
It is a fourth object of the present invention to improve safety by disabling electronic devices when no earthing is provided.
It is a fifth object of the present invention to provide a slide shaft configuration in which only one slide shaft is used which can be retracted in a compact size and which can be operated depending on the work carried out to interpose an object to be worked in the gap of two-armed manipulators.
It is a sixth object of the invention to provide an apparatus for automatically changing tools required for the operation of two-armed manipulators.
It is a seventh object of the invention to provide a tool supplying device capable of picking up tools used in the operation of two-armed manipulators efficiently.
It is an eighth object of the invention to provide a socket changing device used for the attachment and removal of nuts performed by two-armed manipulators.
It is a ninth object of the invention to provide a method of control for a robot vehicle for hot-line job including a base having a slide mechanism on which a manipulator is mounted wherein the position of a slide shaft can be determined by the position and orientation of the finger tip thereof given as target values and wherein slide shafts and the manipulator can be controlled simultaneously.
It is a tenth object of the invention to output operation instructions without manual adjustment operations to align the position and orientation of one arm of a two-armed manipulator with those of the other automatically, thereby reducing the operating time and operability.
It is an eleventh object of the invention to provide a method of performing accurate calibration to determine a basic posture of a robot for which absolute accuracy is required, wherein accurate calibration can be carried out in a short period of time without repeating calibration from the basic posture when the calibration is required as a result of a positional shift or replacement of components.
In order to achieve the first object, according to the present invention, there is provided a robot vehicle for working on live transmission and distribution wires comprising an insulated boom constituted by an insulator which is the end stage of a multi-stage boom rotatably, elevatably and extendably supported on a vehicle for high-place work at the base thereof, two-armed manipulators in a multi-shaft configuration for wiring operations, sliding devices for sliding those left and right two-armed manipulators independently, a suspender arm in a multi-shaft configuration having a function of suspending a heavy object to be supported on an electric wire to allow remote operations by an operator, wherein actuators for driving said two-armed manipulators and said sliding devices are configured on an electrical basis and said manipulator for driving the suspender arm on a hydraulic basis.
In order to achieve the second object, according to the present invention, there is provided a robot vehicle for hot-line job as described above, wherein an umbrella having a gutter to collect rain is mounted on the end of said insulated boom.
Further, said boom has a structure consisting of an extending boom made of FRP or GFRP having a working portion for performing wiring work mounted on the end thereof and a container boom having a roller for guiding and supporting said extending boom, and a silicon compound is applied to a sliding surface of said extending boom.
Alternatively, said boom has a structure consisting of an extending boom made of FRP or GFRP having a working portion for performing wiring work provided on the end thereof and a container boom having a roller for guiding and supporting said extending boom, and an umbrella formed of an insulator and applied with a silicon compound on the surface thereof is provided at a non-sliding portion of said extending boom in no contact with the roller.
In order to achieve the third object, there is provided a robot vehicle for hot-line job as described above, comprising robot controllers for controlling said two two-armed manipulators and generators for supplying power to the robot controllers each provided independently to prevent phase shorting accidents which occur when the two electrical two-armed manipulators in a multi-shaft configuration touch hot lines in different phases simultaneously, wherein the robot controllers and said generators are secured to said base constituted by an insulator and signals are transmitted and received between the two separate robot controllers using an optical cable to provide electrical insulation between the two manipulators.
In order to achieve the fourth object, there is provided a robot vehicle for hot-line job as described above, comprising an earth interlock device which has two conductors provided with connection fittings connectable and securable to a grounding wire on the end thereof and insulated from each other, one or two probes for containing said two conductors having a structure in which said two connecting fittings are insulated from each other, a coil magnetized when said two connecting fittings are connected to the grounding wire, an electromagnetic contactor having a contact capable of enabling operational circuits of electronic devices when said coil is magnetized and a battery for supplying power to said electromagnetic contactor and in which said connection fittings, electromagnetic contactor and battery are connected in series to one of said conductor.
In order to achieve the fifth object, there is provided a robot vehicle for hot-line job as described above, wherein said two sliding devices are mounted in an arrangement such that the interval from each other is increased expanded toward the end.
In order to achieve the sixth object, there is provided a robot vehicle for hot-line job as described above, comprising an automatic tool changer for automatically changing tools required for the operation of said two-armed manipulators provided on said base, wherein the automatic tool changer comprises:
a tool attaching and detaching portion having a key for positioning a tool in a key groove on a manipulator and a clamp button for securing a tool operable in a radial direction and having a restoring force in the direction of moving away from a center axis;
a rack portion having a cylinder for pressing said clamp button when a tool is attached and detached; and
a pneumatic pressure circuit capable of varying the thrust force of said cylinder.
In order to achieve the seventh object, there is provided a robot vehicle for hot-line job as described above, wherein said base comprises a work tool supplying device comprising:
a stand for positioning and holding each work tool;
an intermediate base on which said stand is disposed as required in advance depending on the work;
a general-purpose base common to all kinds of work on and from which a plurality of intermediate bases can be positioned and removed at equal angles or equal intervals: and
a driving portion to and from which both of said intermediate base and general-purpose base can be attached and detached for driving said general-purpose base for angular indexing.
In order to achieve the eighth object, there is provided a robot vehicle for hot-line job as described above, comprising a socket changing device which is a tool for fastening and loosening of a bolt or the like performed by said two-armed manipulators, for pushing a predefined part of a attaching/detaching portion when the tool and a socket are attached together or detached in an axial direction to allow the robot to replace a socket attachable to and detachable from the main body of the tool automatically, wherein the socket changing device comprises:
a cylindrical base for pushing said attaching/detaching portion;
a nut engaging with a polygonal hole of said socket; and
a shaft into which the nut is screwed and which is supported in the base with a spring to be slidable in an axial direction.
In order to achieve the eighth object, there is provided a robot vehicle for hot-line job as described above, comprising a socket changing device which is a tool for fastening and loosening of a bolt or the like performed by said two-armed manipulators, for pushing a predefined part of a attaching/detaching portion when the tool and a socket are attached together or detached in an axial direction to allow the robot to change a socket attachable to and detachable from the main body of the tool automatically, wherein the socket changing device comprises:
a base for urging the attaching/detaching portion at the end of the tool;
a nut having a configuration to engage with a polygonal hole of said socket;
a shaft engaged with the nut so as to allow the same to rotate; and
a cylinder coupled to said shaft to force said nut and shaft to move to a predefined attaching/detaching position.
In order to achieve the ninth object, there is provided a method for controlling a robot vehicle for hot-line job comprising a manipulator including articulated manipulators, a base having slide mechanisms on which said articulated manipulators are mounted and a controller for controlling said articulated manipulators and slide mechanisms, wherein:
to decide the angle of each articulation of said multi-joint manipulators and the position of the base having the slide mechanisms when the position and orientation of the fingertips are given as target values, the position and orientation of said fingertips are given as target values to decide the angle of each articulation of said articulated manipulators and the position of the base having the slide mechanisms by adding the distance between the origins of said articulated manipulators and points at which the positions of the articulated manipulators are decided to control conditions for course calculations to decide the position of the base having the slide mechanisms, thereby controlling the courses of the base having the slide mechanisms and articulated manipulators simultaneously.
In order to achieve the tenth object, the position and orientation of one arm of a two-armed robot are aligned in a desired relationship with the position and orientation of the other arm by reading the position data and orientation data for the arm to be controlled and the arm to serve as a reference and by carrying out a comparison operation to supply an operation command to said arm to be controlled.
In order to achieve the eleventh object, the posture of a robot is calibrated by storing a output value of a position detector of a motor representing the distance from a basic posture determined as a result of accurate calibration to a position where a stopper provided in the operating region of each shaft is hit and by using a position reached by returning from said position where the stopper is hit by said stored output value as basic posture when the posture of the robot must be calibrated.